Handiwork instrument using coreless brushless motor

ABSTRACT

The present invention locates the gravity of a handiwork instrument at the front part by deposing a rotation device right after a tool of the instrument, so that its size is reduced, its operation becomes easier, and its handling is firmed.

FIELD OF THE INVENTION

The present invention relates to a handiwork instrument; more particularly, relates to locating a gravity of a whole handiwork instrument at a front part of a handle unit to obtain a reduced size, an easy actuation and a firm holding.

DESCRIPTION OF THE RELATED ART

A prior art, “A handiwork instrument with a handle”, is proclaimed in Taiwan, as shown in FIG. 10, comprising a handle 7 and a cover 8, where the handle 7 has an axial line. The handle 7 comprises at least a working member 71 for fastening a tool 72; a handle pivot 73 having a revolving axis perpendicular to the axial line for movably pivoting the cover 8; and, at least a containing space 74 at a side of the handle 7 for possessing a room to keep tools 72. The cover 8 comprises an inner surface 81, an outer surface 82 and a cover pivot 83, where the cover pivot 83 of the cover 8 and the handle pivot 73 of the handle 7 are pivoted for the cover 8 to turn between a first position and a second position. When the cover 8 is positioned at the first position, the inner surface 81 has an angle of about 90 degrees to the handle 7; and, when the cover 2 is positioned at the second position, the inner surface 81 is roughly cover the containing space 74 of the handle 7 along the axial line. By the above structure, the handiwork instrument obtains a firm handling and a light weight.

Although the above priro art obtains a firm handling and a light weight, the shape and the size of the priro art depends on the motor size for the motor of the handiwork instrument (not shown in the figure) is usually deposed in the handle 7. Yet, the size of the handle 7 becomes bigger if the size of the motor is bigger, so that, because the handle 7 is designed according to the size of the motor, the handle 7 for the handiwork instrument is bigger and is not conformed to the human-factors engineering. In another hand, the gravity of the handiwork instrument is located at the middle of the handle 7; because the tool 72 is deposed at an end of the handiwork instrument and so the gravity for the operation is not focused on the tool 72, a user has to hold the handiwork instrument at the center of the handle 7 and, at the same time, to add a pressing force to the tool 72 at the end of the handle. In addition, the motor is a general coil sensing motor so that it may be often over-heated with its lifetime shortened. Hence, the prior art does not fulfill users' requests on actual use.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to depose a transmission unit at an end of a handle unit so that a gravity of a handiwork instrument is located at a front part of the handle unit to obtain a reduced size, an easy actuation and a firm holding.

To achieve the above purpose, the present invention is a handiwork instrument using a coreless brushless motor, comprising a handle unit, a transmission device, a sensing unit and a chuck seat, where the transmission device is deposed at an end of the handle unit; the handle unit has a shell; the shell has an axle movably deposed at center; the axle is deposed with a coreless wired stator; the coreless wired stator is connected with a power supply unit to obtain an outside power; the shell has two collar plates inside corresponding to two end surfaces of the coreless wired stator; at lease a collar plate is deposed with a permanent magnet corresponding to the coreless wired stator; a sensing unit senses a pole of the core less wired stator corresponding to that of the permanent magnet; the chuck seat is connected with the axle; and the chuck seat is deposed with a working unit. Accordingly, a novel handiwork instrument using a coreless brushless motor is obtained.

BRIEF DESCRIPTIONS OF THE DRAWINGS

The present invention will be better understood from the following detailed description of the preferred embodiment according to the present invention, taken in conjunction with the accompanying drawings, in which

FIG. 1 is a perspective view showing a preferred embodiment according to the present invention;

FIG. 2 is an explosive view showing the preferred embodiment according to the present invention;

FIG. 3 is a cross-sectional view showing a transmission device of the preferred embodiment according to the present invention;

FIG. 4 is a view showing a sensing unit utilizing CEMF according to the preferred embodiment of the present invention;

FIG. 5 is a view showing a first handle unit according to the preferred embodiment of the present invention;

FIG. 6 is a view showing a second handle unit according to the preferred embodiment of the present invention;

FIG. 7 is a view showing a third handle unit according to the preferred embodiment of the present invention;

FIG. 8 is a view showing an open loop according to the preferred embodiment of the present invention;

FIG. 9 is a view showing a close loop according to the preferred embodiment of the present invention; and

FIG. 10 is a perspective view of a prior art.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The following description of the preferred embodiment is provided to understand the features and the structures of the present invention.

Please refer to FIG. 1 through FIG. 4, which are a perspective view and an explosive view showing a preferred embodiment, a cross-sectional view showing a transmission device of the preferred embodiment and a view showing a sensing unit utilizing counter-electromotive force (CEMF), according to the present invention. As shown in the figures, the present invention is a handiwork instrument using a coreless brushless motor, comprising a handle unit 1, a transmission device 2, a sensing unit 3 and a chuck seat 4, where a gravity of the whole handiwork instrument is located at the front part of the handle unit 1 so that a reduced size, an easy actuation and a firm holding are obtained.

The handle unit 1 is fabricated utilizing human-factors engineering, where the handle unit 1 is cylinder shaped with a concaves part 11 on the surface utilizing human-factors engineering.

The transmission device 2 is deposed at the front end of the handle unit 1; the transmission device 2 has a shell 21 connecting to the handle unit 1; the shell 21 has an axle 22 movably deposed at the center; the axle 22 is deposed with a coreless wired stator 23; the coreless wired stator 23 connects to a power supply unit 24 to obtain an outside power; the power supply unit 24 connects to an on/off switch 241 deposed at a proper place of the handle unit 1; the shell 21 has two collar plates 25 inside corresponding to two end surfaces of the coreless wired stator 23; and, at least one collar plate 25 is deposed with a permanent magnet 26 corresponding to the coreless wired stator 23.

The sensing unit 3 senses a pole of the coreless wired stator 23 corresponding to that of the permanent magnet 26. The sensing unit 3 is a Hall element deposed on the coreless wired stator 23, or at a place corresponding to the coreless wired stator 23 in the shell 2. The sensing unit 3 is connected with an inverter 5 deposed in the handle unit 1 to obtain the pole of the coreless wired stator 23 to control the phase change of the coreless wired stator 23. Besides, the sensing unit 3 a processes a phase change of the coreless wired stator 23 according to a CEMF of a coil of the coreless wired stator 23, as shown in FIG. 4; and, the inverter 5 has a detecting unit 51 inside to receive the CEMF.

The chuck seat 4 is connected with the axle 22 of the transmission device 2; and, the chuck seat 4 is deposed with a working unit 41. Hence, with the above structure, a novel handiwork instrument using a coreless brushless motor is obtained.

When using the present invention, the chuck seat 4 is deposed with a required working unit 41, such as a drill, a polisher or a locking tool; the transmission device 2 is supplied with an outside power by the power supply unit 2; the on/off switch 241 on the handle unit 1 is switched on to contineously process phase changes of the coreless wired stator 23 by the sensing unit 3 to obtain repulsive phases to the permanent magnet 26; as a result, the axle 22 of the transmission device 2 keeps rotating and so the working unit 41 deposed on the chuck seat 4 rotates too for a user to do a required work. Because the transmission device 2 is fixed to the handle unit 1, the gravity of the whole handiwork instrument is located at front part of the handle unit so that a down-pressing force is obtained at the working unit 41 of the chuck seat 4 for an easy actuation.

Please refer to FIG. 5 till FIG. 7, which are a view showing a first, a second and a third handle units according to the preferred embodiment of the present invention. As shown in the figures, the handle unit 1 of the present invention is fabricated according to human-factors engineering; and, besides being cylinder shaped, the handle unit 1 a can be ‘L’ shaped. The handle unit 1 b can be cylinder shaped with a cross handle 12 at an end; or the handle unit 1 c can be cylinder shaped with a grasp handle 13 at a side. And, the human-factors engineering is realized to the various handle units 1 a, 1 b, 1 c.

Please refer to FIG. 8, which is a view showing an open loop according to the preferred embodiment of the present invention. As shown in the figure, when using the present invention, a control unit 63 is deposed on a handle unit 1 according to requirements. The control unit 63 comprises a plurality of switches 61 to control the rotation speed of a transmission device 2 with setup values for the rotation speed, such as speeds of 300 revolutions per minute (rpm), 600 rpm and 1200 rpm, where an open loop control is formed by the transmission device 2, an inverter 5 and a control unit 6. When operating, the user turns on a required tachometer 62 to form a loop with the transmission device 2, the inverter 5 and the tachometer 62 so that the transmission device 2 reaches the required speed according to the setup value of speed for the required tachometer 62 the user turns on. In this way, the rotation speed of the working unit 41 deposed on the chuck seat can be switched.

Please refer to FIG. 9, which is a view showing a close loop according to the preferred embodiment of the present invention. As shown in the figure, in addition to the open loop control formed as shown in FIG. 8, a control unit 63 can comprise a tachometer 62 connected with an axle 22 of a transmission device 2, and a differential amplifier 63 connected to the tachometer 62 and an inverter 5, so that a close loop control is formed by the transmission device 2, the inverter 5 and the control unit 6. When operating, a value for rotation speed is setup in the differential amplifier 63. As the transmission device 2 is turned on and powered, it is rotated in a speed according to the setup value. According to the rotation speed of the transmission device 2 reported promptly and continuously to the differential amplifier 63 in the feedbacks of the tachometer 62, the differential of rotation speed to the setup rotation speed is analyzed. If the differential amount is getting smaller, the commutation speed is turned smaller by the inverter 5 so that the rotation speed can reach the setup value. On the contrary, if the differential amount is getting bigger, the commutation speed is turned greater by the inverter 5 so that the rotation speed can reach the setup value. By doing so, the working unit 41 deposed on the chuck seat 4 is rotated at a fixed rotation speed.

To sum up, the present invention is a handiwork instrument using a coreless brushless motor, where a transmission device is deposed at an end of a handle unit utilizing human-factors engineering so that a gravity of the whole handiwork instrument is located at a front part of the handle unit to obtain a reduced size, an easy actuation, a firm holding, and, furthermore, a stability in use.

The preferred embodiment herein disclosed is not intended to unnecessarily limit the scope of the invention. Therefore, simple modifications or variations belonging to the equivalent of the scope of the claims and the instructions disclosed herein for a patent are all within the scope of the present invention. 

1. A handiwork instrument using a coreless brushless motor, comprising: (a) a handle unit; (b) a transmission device, said transmission device deposing at an end of said handle unit, said transmission device having a shell fixed to said handle unit, said shell having an axle movably deposed at center of said shell, a coreless wired stator deposing on said axle, said coreless wired stator connecting to a power supply unit to obtain an outside power, said shell having two collar plate inside said shell corresponding to two end surfaces of said coreless wired stator, a permanent magnet deposing on at least one collar plate, said permanent magnet corresponding to said coreless wired stator; (c) a sensing unit, said sensing unit sensing a pole of said coreless wired stator, said pole corresponding to a pole of said permanent magnet; and (d) a chuck seat, said chuck seat connecting to said axle of said transmission device, a working unit deposing on said chuck seat.
 2. The instrument according to claim 1, wherein said handle unit is ‘L’ shaped.
 3. The instrument according to claim 1, wherein said handle unit is cylinder shaped having a concaves part at a place for hand-holding.
 4. The instrument according to claim 1, wherein said handle unit is cylinder shaped having a cross handle at an end of said handle unit.
 5. The instrument according to claim 1, wherein said handle unit is cylinder shaped having a grasp handle at a side of said handle unit.
 6. The instrument according to claim 1, wherein said sensing unit connects to an inverter deposed in said handle unit to recieve a pole of said coreless wired stator sensed by said sensing unit; and wherein said sensing unit controls a phase change of said coreless wired stator.
 7. The instrument according to claim 6, wherein said inverter has a detecting unit inside said inverter to receive a counter-electromotive force (CEMF).
 8. The instrument according to claim 1, wherein said sensing unit is a Hall element; and wherein said Hall element is deposed in said shell at a place corresponding to said coreless wired stator.
 9. The instrument according to claim 1, wherein said sensing unit processes a phase change of said coreless wired stator according to a CEMF of a coil of said coreless wired stator.
 10. The instrument according to claim 1, wherein said transmission device connects to a control unit deposed on said handle unit; wherein a circuit is obtained through said control unit and said transmission device to control a rotation speed of said transmission device.
 11. The instrument according to claim 10, wherein said control unit comprises a plurality of switches controlling rotation speeds of said transmission device; and wherein an open loop is obtained through said transmission device and said control unit.
 12. The instrument according to claim 10, wherein said control unit comprises a tachometer, connecting to said axle of said transmission device, and a differential amplifier, connecting to said tachometer and said inverter. 